Re: Autovon locations
- Alright, I'll answer this again.
The 14-edge blinders corrected a side-lobe problem in azimuth for horizontal polarization. They effectively made the antenna 12-20 db less sensitive to signals coming in from 'the corner of its eye' as it were. Mostly used in congested areas, where a horn could 'see' other antennas on parallel or converging routes.
The 'front porch' blinder corrected a strong downward lobe caused by the weather cover. The smooth and slightly bowed weather cover caused strong back-reflection of the plane wave passing through the aperture. The 15-deg forward tilt of the weather cover effectively produced a 30-degree off-axis reflection back into the antenna which was, in turn, focused to a virtual point about 60-degrees below bore-sight. The lobe would interact with fore-ground objects prone to strong back-scatter or even retro-reflection, like buildings and trees, providing a side-to-side coupling path between Tx-Rx antenna pairs. The porch did not reduce the off-axis lobe but literally reflected it upward and away from the horn aperture.
Both lobe problems result from the unique geometry of the KS15676. The circular well-shielded aperture of a conical horn-reflector does not exhibit these anomalies.
Some horns have blinders, some have porches, some have both, some have neither. The use of blinders depended strongly on a horn's local situation....waw...
--- In firstname.lastname@example.org, Mike Cowen <mcowen@...> wrote:
> I noticed all the trapezoidal horns have the
> "front porch" mod, but none have the sawtooth
> side blinders. In what cases would you use one vs. the other, but not both?
>> http://22.214.171.124:8080/docushare/dsweb/Get/Document-4602/1965-07-01%20Thu.pdfI found it OK, but note it's newspaper page 3, pdf page 6
> I'm getting the following error:
> License Exception: Invalid license
> A DocuShare license maximum concurrent guests limit was exceeded.